Radio 101 Reference Version 3 Feb 2017 https://w7jcr.wordpress.com/ Page 1
Topics 1. Emergency Communications 2. Radio Modes a. Simplex b. Repeaters 3. Programmed Frequency List Highlights 4. Radio Propagation 5. FM Modulation 6. CTCSS 7. Internet VoIP Modes a. Echolink b. IRLP Page 2
Emergency Communications Practice communicating before the emergency Wednesday 0900 roll call net Channel 1 = PTREP Wednesday 0930 roll call net Channel 12 = MIRPT Wednesday 1900 roll call and education net Channel 1 = PTREP Maintain supply of non-rechargeable batteries Upon disaster or emergency Take care of you and your family first Go to Channel 1 = PTREP (Port Townsend Repeater) Listen for a net control requesting and gathering info Listen on your neighborhood FRS channel Communicate clearly and precisely (radios may be on battery power) Alternate EOC Activated if Main EOC inoperative Simplex operation Channel 6 = OPAREA1 (146.4) Port Townsend, Cape George, Beckett Point, Kala Point, Tri-Area, Marrowstone Page 3
www.jeffcoeoc.org Page 4
Ham Radio Can Bridge to Beyond Disaster Area for Health and Welfare Traffic Distant VHF/UHF Repeater HF, Satellite Normal Internet Telephone Yellow = Local Disaster Area Blue = Regional Disaster Area Black = Unaffected Area Page 5
Radio Modes Most 2 meter and UHF FM radios Receive or Transmit at a given time Push to Talk, then Release to Listen Simplex Transmitter and receiver on the same frequency 0 MHz offset Repeater Transmitter and receiver on different frequencies +/- 600 KHz on 2 meters +/- 5 MHz on UHF Page 6
Simplex mode Direct radio to radio communication Good for emergency communications Just 2 end point radios for complete communication Generally limited communication range Can be on the output of a repeater if repeater fails because others are listening there Page 7
Simplex Radio Communication TX-1 TX-1 RX-1 RX-1 Channel 6 = OPAREA1 Alternate EOC Fire Station 16 Ham #1 Everyone can communicate if within communication range TX-1 RX-1 Ham #2 Page 8
Simplex Radio Communication TX-1 TX-1 RX-1 RX-1 Channel 6 = OPAREA1 Alternate EOC Fire Station 16 X Ham #1 What if Ham #1 needs to talk to Ham #2 but they are too far apart or path is obstructed? TX-1 RX-1 Ham #2 Page 9
Repeaters A transmitter and receiver placed in a good (generally higher) location to receive signals and simultaneously retransmit or repeat signals Transmitter and receiver frequencies are separated by an offset so that simultaneous reception and transmission is possible Repeaters usually have a time out timer that will turn off the repeater transmitter if a received signal lasts more than perhaps 10 minutes Page 10
Communication Using a Repeater 145.15 MHz TX-1 TX-2 144.55 MHz Offset=600KHz Offset= -600KHz 144.55 MHz RX-2 RX-1 145.15 MHz Channel 1 = PTREP Morgan Hill Port Townsend Ham #1 All communication is repeated from RX-2 to TX-1 TX-2 RX-1 144.55 MHz Offset= -600KHz 145.15 MHz Ham #2 Page 11
2m and UHF Repeaters in Washington Page 12
Programmed 2m and UHF Repeaters Page 13
Programmed Frequency List Highlights RT=Repeater S=Simplex RX=Receive Only Page 14
Radio Propagation Generally visual line of sight on 2m and UHF Reflections off of buildings or mountains Combination of direct and reflected paths can cause multipath fading or distortion Moving as little as 6-18 can make or break your signal If you find a good spot, do not move around much during contact Added path loss if obstructed Terrain Vegetation Inside vehicle Building Relocate to increase height above ground or nearby obstructions Second floor window Speaker microphone allows holding radio antenna higher External antenna above roof top Page 15
FM = Frequency Modulation Stronger radio signals cover up receiver noise or quiets the receiver Receiver squelch keeps radio muted until a signal is received A carrier squelch receiver receives all signals Useful to hear all signals on a frequency CTCSS receivers only unmute when matching CTCSS encoded signals are heard Page 16
CTCSS Continuous Tone Coded Subaudible Squelch CTCSS decode keeps a receiver muted until a desired signal is heard, a repeater for example You need CTCSS encode to talk through repeaters CTCSS uses 67-250 Hz tones below 300-3000Hz communication voice audio Recommended that simplex be carrier squelch with CTCSS turned off Page 17
Internet Voice over IP Modes Regional and Global Voice Communication Echolink (~5,455 Nodes Worldwide) www.echolink.org Radio to Radio Radio to Computer (license verification) Computer (license verification) to Computer (license verification) IRLP (~1,746 Nodes Worldwide) www.irlp.net Radio to Radio only Local Internet probably down Your VHF/UHF radio might reach to distant Echolink or IRLP node with undamaged and uncongested Internet Documentation and Training soon Jefferson County Repeater Echolink=714974 (Search for W7JCR) Internet to radio only Marrowstone Island Repeater IRLP=4251 Echolink=227301 (Search AH6EZ) Internet to radio and radio to Internet Non-standard user interface Page 18